PROJECT SUMMARY/ABSTRACT Alcohol misuse remains a major public health problem in emerging adults (age 18-25). Excessive drinking is the largest source of morbidity and mortality in this age group and predicts subsequent alcohol problems across the lifespan. Although most emerging adults ?mature out? of hazardous drinking and transition into moderate use, many continue a developmentally persistent pattern of alcohol misuse, and the predictors of differential trajectories remain largely unknown. A large number of cross-sectional studies have found significant associations between alcohol misuse and indices from behavioral economics, thus we are currently conducting a longitudinal investigation of behavioral economic indicators as processes in regular binge drinkers from their early twenties (21-24) to their mid-twenties (24-27). However, this ?parent? R01 study does not include any measures of biological risk factors, so the proposed R21 study aims to collect neurophysiological measures of reward processing in a subsample at two timepoints spaced 8 months apart during the parent longitudinal study. The neurophysiological measures include two event-related potential (ERP) components that are robustly associated with reward processing: (1) P3, which reflects the incentive salience of alcohol-related vs. alcohol-free stimuli and (2) Reward Positivity (RewP), which will reflect sensitivity to immediate versus delayed reward. These ERP data would permit systematic investigation of the ERPs as biomarkers of persistent alcohol risk, a substantially understudied relationship in the existing literature. To address this question, the study will recruit 355 participants from the existing study to complete additional EEG sessions during already-scheduled study visits. This study has two primary aims. The first aim is to integrate cross-sectional neurophysiological measures into the ongoing longitudinal study to examine the utility of these measures to predict problematic alcohol use individually and in conjunction with behavioral economic indicators. The second aim is to determine correspondence between longitudinal changes in neurophysiological and behavioral economic indices of risk and their relations to alcohol misuse. Longitudinal models will be used to examine if changes in the neurophysiological indicators are responsible for changes in alcohol misuse over time and to disentangle overlapping versus independent influences.